Slot car racer



y 1965 F. J. RANNALLI 3,195,472

SLOT CAR RACER Filed u 1964 2 Sheets-Sheet 1 INVENTOR. 1 :0 JfAw/vmuFOWZEIF K/I/OBBE GAMBIPEAL July 20, 1965 F. J, RANNALL] 3,195,472

SLOT GAR RACER Filed June 5, 1964 2 Sheets-Sheet 2 INVENTOR. 17950JZA/V/VALL/ BY ran/4E2, mvoeas 64M51ELL United States Patent 3,195,472SLOT CAR RACER Fred J. Rannalli, Santa Ana, Calif, assignor to James B.Gambrell Filed June '5, 1964, Ser. No. 372,905 (Ilaims. Cl. 104-60) Thisinvention relates to self-propelled miniature scaled toys, and moreparticularly to improvements in the slot guide suspension systems of toyautomobiles moved along a slotted track by an electrical motor.

Slot car race-rs, scaled to or size of their real counterparts, havebecome quite popular. The electric motors used are normally energized byconductor strips or bars disposed on each side of the center slot andthe motors speed is controlled by a portable variable resistor whichcontrols the amount of current that flows through the motor winding.

The motors currently used on such racers are capable of such high speedsthat attention has been given increasingly to banking the tracks andimproving the overall roadability of the racers. Conventional speeds arenow so high that the racers are made as light as possible and theircenters of gravity designed to be close to the roadbed.

Many prior art toy racers of the kind adapted to be used on slottedroadbeds employ a slot guide connected to the fixed frame of the toywith a pair of contacts or brushes connected on each side of the slotguide to make contact with the conductor bars affixed to the track oneach side of the slot. Later prior art racers in an effort to improveroadability have used a slot guide assembly which turns the front wheelsas the slot guide is carried around a curve of the roadbed. While theseprior art devices may have much to commend them, none will permit aracer to course a typical oval track at a high rate of speed unlessspecial care is given to suspension, weight distribution and the like.

The present invention constitutes a breakthrough in slot guidesuspension systems. By following the inventive concept disclosed herein,nearly any racer can attain speeds which were heretofore believedunobtainable without sophisticated design of all parts of the slot car.Moreover, the substantial improvement in the readability of slot carracers obtained by the present invention may be easily incorporated intomany existing racers.

The present invention utilizes a slot guide arm pivotally mountedtowards the rear of the frame of a slot car so that the front of the carand the arm can move in vertical directions relatively independently ofeach other. The forward end of the arm is also weighted so that the slotguide carried thereon remains in the slot as the racer moves over thetrack. The composite result of the pivot arrangement and weighting issuch that the slot guide tends to be driven into the slot as the speedis increased and the cars ability to take curves without derailing isimproved substantially.

Tests of racers utilizing the principle of this invention have shownthat its transfers the major ingredient of competition between slot carracers from that of specially designing racers to that of merelycontrolling the racer by the variable resistor control. Thus, thisinvention puts most slot-oar racing competitors on an even footingwithout their having to develop the special design know-how for buildingracers.

Whereas a great deal of effort in the past has gone towards working outways in which the front wheels can be turned as the slot guide followsthe slot on a curve in order to improve a racers ability to negotiatecurves at higher rates of speed, the present invention distributes theweight on the front and rear wheels of the slot car racer so that thefront wheel-s act more as a touch-down or contact points and do notcontribute to the turning characteristics of the racer. In fact, becausethey are not directly connected to the slot guide arm at all, they slidecrossways on the track as the slot guide arm carries the heavier rearpart of the racer around a curve.

Broadly speaking, the present invention is improved slot guidesuspension means comprising a slot guide arm having a slot guidedepending from one end, means connecting the other end of the arm to theframe of the car so that the arm is movable in a vertical plane and withthe slot guide disposed toward the front of the car and means urging theslot guide and arm towards the track so that the slot guide ridesinterior of the slot as the car moves over the roadbed.

More specifically, this improved suspension means combines .a slot guidearm having a slot guide depending from one end; means pivotallyconnecting the other end of the arm to the frame of the car for verticalmovement with the slot guide disposed toward the front of the car andnormally depending below the plane of the roadbed; and weight meansassociated with the forward end of the arm to urge it downwardly towardsthe track so that the slot guide tends to be driven into the slot of theroadbed as the car move-s thereover.

Another feature of this invention pertains to a variable length slotguide suspension arm formed by a pair of tubular member, one telescopedwithin the other, so that the relative length of the slot guidesuspension system can be changed to work with different size frames andracer bodies.

In a more limited sense, the present slot guide suspension meanscomprises a tubular slot guide arm pivotally connected to the frame of aracer forward of its rear axle for movement in a vertical planetransverse to the axles of the racer; an arm extension telescopedinterior of the slot guide arm to permit adjustments in the overalllength of the arm; a lead weight of preselected magnitude afiixed to theforward end of the arm extension; a plastic slot guide supported in theweight for rotation about a vertical axis; and a pair of contact brusheselectrically connected to the motor affixed to each side of the slotguide to contact the conductors bars on the roadbed.

In addition to the improvement in slot guides suspension means per se,the present invention also envisages a complete frame and slot guidesuspension system for sel propelled slot car racers wherein the frameassembly can be adjusted to change the front-to-rear axle separation toaccommodate different size bodies just as the slot guide arm can bevaried in length.

These and other objects, advantages and features of the presentinvention may be more fully understood when the following detaileddescription is read with reference to the drawings in which:

FIG. 1 is an exploded perspective of the frame and guide suspensionmeans of a slot car racer constructed in accordance with the presentinvention;

FIG. 2 is a side view of a slot car racer illustrating the relationshipbetween the frame, slot guide suspension means, and front and rearwheels;

FIG. 3 is a front view of the frame and slot guide suspension means ofthe present invention;

FIG. 4 is a bottom view of the slot car racer constructed in accordancewith the present invention;

FIG. 5 is a plan view of the weight and slot guide taken along line 55of FIG. 2;

FIG. 6 is a front view taken along broken line 66 of FIG. 4 toillustrate the restoring couple of the slot guide suspension arm as acar negotiates a curve;

FIG. 7 is an alternative embodiment of the slot-car frame illustrated inFIGS. 1-5 wherein the rear wheels are not part of the motor assembly;and

FIG. 8 is a partial perspective of an alternative embodiment of the slotguide suspension means designed to put the point of attachment oftheslot guide suspension further outboard of the frame member.

In the first exemplary embodiment of the invention as illustrated inFIGS. 1-6, the slot car racerw can be seen to include a frame ;a'slotguide'suspension system l l, a motor and rear wheelassembly "12, afront axle 13,;front. Wl166lS 16, and a plurality of body attachmenttabs ,18.

The frame assembly 10 comprises an H-shaped rear section 21, which isformed by a pair oftubular members 22 held in a spaced-apartpara'llelrelation by atransverse pin 23 affixed at each of its end to the tubularmembers" 22. Apertures 24 are provided on the rear end of the" H-shapedframe section 21 to holdjthe motor and rear wheel assembly 12 thereon,e.g. by screws 26. p A front frame section 31 generally in the shape ofa U is also provided, formed of'two tubular members 32 spaced apart inparallel relation and held thereby a front axle bearing or hollow tube33 through which the front axle 13 is disposed. The endsof axle 13 arethreaded to mount the front wheels 16 and lock nuts 17 hold them on, The

outside diameter of tubular members 32 are" smaller than the insidediameter of tubular members 22 of rear section 21, and are adapted totelescope interior of the members 22' so that the front-to-rear axledistance on the frame can be varied to mount diiferent size bodies onthe frame. A plurality of outwardly disposed tabs 18, which can be i tothe ,roadbed. In the FIG; 6 view, the wheels are shown in an exaggeratedcondition as; they would be if the racer ere going around'a' left curve.I s i With the general organization of parts illustrated in FIGS. ,15, aracer havingthe; dimensions and weights shown in FIG. 7 has been. foundto work quite well. The pertinent data is as follows: {54 scale model;Model.DC7,05

, motor manufactured by the Pittman, Corporation of Sci:

bent at their ends in upstanding relation 41 are provided to secure abody 24! tothe frame. 42 hold the body 20. v The slot guide assemblysuspension means 11 includes Self-threading screws a T-shaped slot guidearm 51,.the cross segmentof the T: I being pivotally supported on thepin 23 for rotation in a vertical plane between and roughly parallel tothe tubular members 32 and 22. A slot guide extension 56 is telescopedinterior of the tubular leg 53 of the T-shaped arm 51 and, a lead weight58 is atfixed to the forward end (to the right of FIG. 1) of the slotguide extension arm 56. A metallic circular liner or bushing 61 isforce-fitted into the Weight 58 and is adapted to receive the shaft 65on the slot guide 66 so that it can pivot along a vertical axis as theracer is moved over the track.

The slot guide 66 is formed of nylon, Teflon, or some. comparableplastic. sleeve or bushing 61 in the weight 58. Slot guide 66 hasapertures67 which receive screws 68"to hold a pair of Normally itjispress-fitted into the i 'ler'sville, Pennsylvania;front-torear'axledistance of approximately 3% inches; slotguide.suspension'assembly 11. pivotally supported (on a pin 23.)approximately -one' inchforwardrof theirear axle; weight center ofthe-2% to S-ounce motor located approximately inch forward of the rear.axle; .arm weight of approximately /2 ounce.

, Thesedistribute the weight between the. rear and .front wheel in aratio of approximately 4: 1.,

In the event the axle-to-axle distance is increased substantially, it isdesirable. to increase the weight slightly.

For example, with; an axle-t-o'-axle spacing of approximately'4Vzinches,'the slot' guidefassembly appears to work 7 betterwithafik-ounce. weight on arm extension 51.

While it isfnot certain. just why the: present invention realizes suchasubstantial improvement in slot car racer perforance and, even thoughthe reason for the superlor performance is really immaterial,v thefollowing tentative explanation is offered: r

Theweight attac'hed'to the front; of the'slot guide assembly holds theslot guide in the slot and prevents interruptions ofthe electrical pathwith its attendant spurting, which performance degrades the stability ofa racer.

The :weight also constitutes a lifting force for the weight of the racerjust forward of the center of gravity of the motor. As the racer movesalong the r-oadbed, the weighted slot guide'tends to be driven into thetrack 1 which, in an opposite sense, offsets part of the weight ofbraided contacts or brushes 69 so that they can engage the conductorbars 71 disposed on each side of the slot 72 of the roadbed (see FIG.2). The brushes 69 are'con- .nected to the terminals of the motor byleads 55.

The relationship of the slot guide to the roadbedcan be seen best inFIG. 3. p The conductor bars .71 are disposed on each side of the slot72 and the lower end 73;

of the slot guide assembly 66 fits interior of the slot 72.

and acts to guide the racer as it moves along the roadbed. It will benoted that the slot guide suspensionassembly little forward'of the motor81. Of course, the motor and Wheel assembly 12 need not be a separateassembly; instead the wheels could be connected to the-frame asillusstrated in FIG. 7. In this latter case, the motor will be aseparate unit adapted to'fit on the frame 10 in order to rotate the rearwheels 14.

the motor byproviding a lift to the front end of the frame (at itspoint'of' attachment). As a result, as the car enters a curve the frontpart of the raw: carries less of the weight of the frame and the motor.Thus, the front 11 is pivoted on the frame aboutaxis 23 at. apointwheels slideacross the track with less resistanceiin re-.

sponse to the turning'force set in motion by the slot guide moving alongthe" curving track. The front wheels really *act as stabilizing points,not as wheels in theconventional F -t-F 'phflS .the'forceat the pivotpoints F attributable to the weight ,W These relations can be obtainedby taking the sum of themoments about the various points high as thedotted outline indicates, the slot guide continues to ride in the slot72 and carry the rear'wheels and rear part of the frame assembly withit. Thus, instability of the front" wheels, 16 of the raceriwilli. haveOver and above the static lift, the dynamic forces opposing the movementof'the motor away from the track are concentrated at theirear axle andjust forward of the. motor (atv the pivot'point forthe'arm). Not onlydoes the weighted suspension arm tend to return the motor and frame tothe roadbed or hold it there, but the transverse twist on the armestablishes couple A which counteracts the centrifugal force of themotors weight as a curve is being negotiated. I V V r FIG.ti-"illustrates another embodiment of'the slot guide suspension arm. Inthis case, an A-type slot guide sus pensioniassembly 91 is provided. Apair of arms 94 are. .pivotally connected to a pin'92 outboard'of thesidesof the frame 93to provide .additional stability; The slot;

' guide suspension arm 91 functions essentially like" the T-suspensionassembly 11; however, the restoringjcouple,

illustrated in FIG. 6 as A, is greater because its operates at pointsfarther outboard of the frame.

The frame and slot guide suspension system is easy enough to assemblefor a variety of body sizes. After determining the proper axle-to-ax-ledistance to accommodate the body, it is attached to the outwardlyprojecting tabs 18, the tubular members 22 are crimped on the tubularmembers 32 and tubular member 52 is crimped on the extension 56 of thesuspension arm so that the weight and slot guide are forward of thefront axle 33. The ends of the outwardly projecting tabs 18 are bentupwardly and the body is connected thereto by screws 42.

While the present invention has been explained with respect to differentillustrative embodiments, it should be apparent to those skilled in theart that other changes and arrangements are contemplated which comewithin the ambit of the present teaching. For this reason the inventionshould be limited only to the extent of the appended claims.

What is claimed is:

:1. In a slot car race-r of the type designed to be guided along a trackby a longitudinal slot formed in the roadbed thereof and having anelectric motor energized by a source of power associated with theroadbed, the improvement in the slot guide suspension means comprising,

a slot guide arm having a slot guide depending from one end,

means connecting the other end of said arm to the frame of the car sothat the movement of said arm is substantially restricted to a verticalplane and said slot guide is disposed toward the front of the car, andmeans urging said slot guide and arm downwardly toward the track wherebythe slot guide rides interior of the slot in the roadbed as the carmoves thereover.

2. In a slot car racer of the type designed to be guided along a trackby a longitudinal slot formed in the roadbed thereof and having anelectric motor energized by a source of power associated with theroadbed, the slot guide suspension means comprising,

a slot guide arm having a slot guide depending from one end,

means pivotally connecting the other end of said arm to the frame of thecar for movement substantially restricted to a vertical plane, said slotguide disposed forward of the front axle of the car and normallydepending below the plane of the roadbed, and weight means urging saidarm downwardly toward the track whereby said slot guide tends to bedriven into the slot in the roadbed as the car moves thereover.

3. A frame and slot guide suspension system for a selfpropelled slot carracer of the type designed to be guided by a longitudinal groove in thetrack roadbed comprising, in combination,

a frame assembly having front and rear axles and Wheels rotatablymounted thereon,

means cooperating with said rear wheels to drive the slot car, a slotguide mounted on a support member, means pivotally connecting saidsupport member on said frame for movement which is substantiallyrestricted to a vertical plane, and

means urging said guide downwardly so that it ride-s interior of thelongitudinal slot formed in the roadbed as the car moves thereover.

4. A frame and slot guide suspension system for a selfpropelled slot carracer in accordance with claim 3 wherein said frame assembly and supportmember are adjustable to change the overall length of the frame and slotguide suspension system for different size racer bodies, and

said means urging the guide interior of the slot can be changed toprovide a normal force at said slot guide of a desired magnitude.

5. A frame and slot guide suspension system for selfpropelled slot carracers of the type designed to be guided by a longitudinal groove in theroadbed of the track comprising, in combination,

a frame having tubular side members spaced apart in parallel relation,

axle support means affixe-d to the forward end of said frame; a frontaxle rotatably supported in said axle support means;

a transversely oriented pin connected between the side members towardtheir other ends;

an arm pivotally connected to said pin at one end so that its rotationis substantially restricted to a vertical plane,

the forward end of said arm terminating forward of said axle support;

weight means attached to the forward end of said arm;

a slot guide pivotally supported in said weight means for movement in aplane roughly parallel to said roadbed;

means including the rearward part of said frame to support a rear axle,wheel and motor assembly; and

means operable to change the longitudinal distance between front andrear axles of the racer to accommodate different size racer bodies.

6. A frame and slot guide suspension system for selfpropelled slot carracers in accordance with claim 5 wherein the Weight of the propellingmeans and the magnitude of the weight means and their locations on theframe are selected to distribute the weight on the rear and front wheelsof the racer in a ratio of approximately 4: 1.

7. A frame and slot guide suspension system for a selfpropelled slot carracer of the type designed to be guided by a longitudinal groove in atrack comprising, in combination,

:a forward frame section having a pair of parallel tubular side member-sconnected at their forward ends by a transversely oriented tubularbearing to support the front axle and wheels of the racer;

a rear, H-shaped frame section having a pair of parallel tubular sidemembers;

the forward ends of said rear tubular side members spaced apart totelescope over said forward side members;

a transverse pin connected between intermediate parts of said reartubular members to maintain said side members in spaced-apart relation;

means including the other set of ends of said rear tubular members tosupport the rear axle and wheels and the propelling means for saidracer;

body support tabs aflixed to each of said tubular members and extendingoutwardly therefrom;

A T-shaped tubular slot guide arm having the tubular cross of theT-supported on said pin to permit rotation in a longitudinally disposedvertical plane;

a tubular slot guide arm extension telescoped interior of the leg of thetubular slot guide arm and extending forward beyond the front axle ofsaid slot car;

:a slot guide mounted at the forward end of said extension to ride inthe groove in said tracks; and,

means urging said slot guide interior of said groove as the racer movesover the roadbed.

8. A frame and slot guide suspension system in ac cordance with claim 7wherein said means urging said slot guide interior of said slot in theroadbed as a preselected weight aflixed to said forward end of saidextension arm adjacent said slot guide; and

said slot guide is pivotally mounted in said weight for rotation in aroughly horizontal plane.

9. In a self-propelled slot car racer of the type designed to be guidedalong a track by a longitudinal slot formed in the roadbed thereof andhaving an electrical motor energized by a source of .power connected toconductor 7 v bars'on each side of the. slot, the improvement in slotguide suspension means comprising ,1 r a a tubular slot guide 'armpivotally connected at one end to the frame of a racer forward of therear axle for movement only in .a generallyfvertical plane trans- I aplastic slot guide supported'tby said Weightfor r0tation about avertical axis; and I a pair of contact brushes electrically connected tothe motor aflixed to each side of said, slot guide to contact theconductor bars onthe roadbed.

. 10. A frame and slot guide suspension system for a selfpropelled slotcar racer of the type designed to begui-ded by a longitudinal groove inthe track roadbedzcomprising, in combination, a a

aslot.guide;and,'

,a frame-assembly having front and rear'vaxles and Wheels'rotatablymounted thereon; r 1 means associated with some of saidv wheels operableto drive the slot car along the track; a v I 1 I a support'member.having its movement restricted genv. erally to a vertical plane bothpivotallylconnecting thesslot guide to the frame assembly and urging theslot guide to ride interior of the longitudinal groove formed in thetrack.

7 lieferen'cesfiited hy the Examiner 1 UNITED STATES PATENTS 1,704,012 I3/29 'Marx 104-173 1,981,655 '11/34' Lucke 104-445 3,163,123 12/64Ziroli -1. 104-60 ARTHURIL. LA POINT, Primary Examiner I '20 MILTONBUCHLER, Examiner.

1. IN A SLOT CAR RACER OF THE TYPE DESIGNED TO BE GUIDED ALONG A TRACKBY A LONGITUDINAL SLOT FORMED IN THE ROADBED THEREOF AND HAVING ANELECTRIC MOTOR ENERGIZED BY A SOURCE OF POWER ASSOCIATED WITH THEROADBED, THE IMPROVEMENT IN THE SLOT GUIDE SUSPENSION MEANS COMPRISING,A SLOT GUIDE ARM HAVING A SLOT GUIDE DEPENDING FROM ONE END, MEANSCONNECTING THE OTHER END OF SAID ARM TO THE FRAME OF THE CAR SO THAT THEMOVEMENT OF SAID ARM IS SUBSTANTIALLY RESTRICTED TO A VERTICAL PLANE ANDSAID SLOT GUIDE IS DISPOSED TOARD THE FRONT OF THE CAR, AND MEANS URGINGSAID SLOT GUIDE AND ARM DOWNWARDLY TOWARD THE TRACK WHEREBY THE SLOTGUIDE RIDES INTERIOR OF THE SLOT IN THE ROADBED AS THE CAR MOVESTHEREOVER.